Learn by reading articles and following the tutorials. By reading, undestanding the ideas, and embracing the concepts you can improve your expertise in the following areas:
Code&Coffee - webinars and workshops where you can sharpen your skills and gain knowledge about up-to-date technologies: modern languages, trendy frameworks, and best practices. For the beginners it is an unique and rare opportunity to learn from the experienced developers. For the professionals it is an easy way to catch up something new.
I own a few open-source projects on GitHub and appreciate any help: Wiki articles with use cases, code reviews, proposals, and pull requests with bug fixes or improvements.